1. Field of the Invention
The present invention relates to an apparatus for making, in a process for high-pressure liquefaction such as direct liquefaction of coal, supply of the raw material and relief of the pressure of the reaction product liquid.
2. Description of the Prior Art
Referring first to FIG. 1 illustrating a conventional process for liquefaction of coal, the material slurry in a slurry tank 1 is supplied into a high-pressure reaction vessel 3 by means of a high-pressure slurry pump 2. The slurry liquefied in the high-pressure reaction vessel 3 is discharged to the outside of the system through a reducing valve 4. The product slurry obtained as a result of the reaction is a high-pressure slurry containing product oil, unreacted coal, ash and other heavy metals.
In the conventional system, the relief of the pressure of the product slurry has been made by means of the reducing valve 4. According to this pressure relieving method, however, the gases dissolved in the slurry are separated at once to interrupt the flow of slurry, because the relief of the pressure is made abruptly while the high pressure product slurry flows continuously as a jetting flow. This inconveniently causes various problems such as a water hammering, erosion of the valve and so forth, resulting in a shortened life of the system. In addition, since the relief of pressure is made by letting the high-pressure slurry flow out through the reducing valve, the energy of the pressure is uneconomically wasted. Also, the high-pressure slurry pump 2 in this type of system has to deliver the material slurry of high concentration at a high pressure, causing various technical difficulties.
As a countermeasure for recovering the loss of pressure energy, it has been proposed to continuously feed the slurry making an efficient use of the pressure of the slurry supplied from a supply chamber to the outside of the system. This type of apparatus is shown, for example, in the specification of the U.S. Pat. No. 4,112,047.